Liquid crystal displays (LCDs) show a tendency that its application field is gradually increased due to the characteristics such as light weight, thin thickness, and low-power-consumption driving. Owing to this tendency, the LCDs have been used for office automation equipment, audio/video equipment, and so on.
Meanwhile, the LCDs adjust an amount of transmitted light and image signals applied to a plurality of control switches arranged in a matrix pattern, thereby displaying a desired image on a screen.
Since such the LCDs are non-emissive devices, the LCDs requires a light source such as a backlight. The light source for the backlight includes a cold cathode fluorescent lamp (hereinafter, referred to as “CCFL”).
Such a lamp is driven by receiving an alternating current (AC) signal having high voltage through a lamp driving circuit. However, when driving the lamp, the lamp may be opened due to defects and erroneous input voltage thereof. Accordingly, an open lamp protecting circuit is necessary to detect the open state of the lamp and protect the lamp driving circuit.